DEC Pro 350/380 Memory Cards - Interchangeability?

Ethan Dicks ethan.dicks at
Fri Sep 2 14:05:58 CDT 2016

On Fri, Sep 2, 2016 at 2:44 PM, Paul Koning <paulkoning at> wrote:
> Incidentally, the Pro technical manual says that the daughterboard can be up to 2 MB (but DEC only offers 512 kB).  It doesn't say how that is done.  It looks like the answer is that there are four RAS signals, so you can have four banks, 256k by 16 each.

Hmm... 2 Daughterboards at 2MB each?  A full 22-bit boat of RAM?
Sweet!  I have more than one Pro - I started upgrading one with
256kbit DRAMs.  I also had a PSU smoke on my Pro380 and got a
replacement but haven't installed it yet.  I'm already in "repair all
the PDP-11s" mode, so I'll add it to the stack.  Someday, I'll get
2BSD up on at least one of them (for now, I have RT-11 and Venix)


More information about the cctalk mailing list